The present invention relates to a coupling for driving a shaft or the like from a power drive, and more particularly, to an automatic slip coupling assembly which automatically disengages a conveyor roller from the power drive in the event of a jam-up of parts transported by the conveyor.
Conveyor system are known which have one or more power driven rollers and a plurality of freely rotatable guiding rollers supporting and guiding the conveyor belt. In a factory or the like, various parts are placed onto the conveyor to be transported to various locations in a plant, and it is common to have jam-ups when the parts are not taken off the conveyor as quickly as they are put onto the conveyor or when the parts become blocked for some reason. The conveyor driving mechanism, conveyor rollers, or the parts themselves may be damaged if the conveyor is continously powered, and it is not stopped when a jam-up occurs. Thus, it is desirable to provide some means for stopping the conveyor when a jam-up or blockage of the items being transported causes a slow-down or stoppage of the conveyor belt.
Manual controls may be used to stop the conveyor when a jam-up occurs, but an operator is required full-time to watch over the conveyor system and to actuate the controls when necessary. This is not desirable because it is an expensive use of personnel who could be used for other jobs. Further, the additional controls required are expensive and are subject to failure.
Typical automatic shut-off devices which may be used to selectively stop a conveyor system, including slip clutches and other mechanisms, are expensive and complex. Because of the enormous number of shut-off devices that are required for existing or new conveyor systems, it is not feasible to utilize existing shut-off devices, and many of the known devices could not be installed or would be extremely expensive to install in existing or new conveyor systems.
Thus, the present invention was devised to provide a simple, coupling assembly for driving a conveyor roller which automatically disengages the conveyor roller from the power drive when the conveyor is jammed or blocked, thereby avoiding the necessity for shutting down the system.
Another problem with existing conveyor systems is that heavy parts such as engine heads, blocks, or the like are thrown onto the conveyor for transportation. Each conveyor roller typically has a core opening through which a mounting shaft passes, and the roller is either fixed to the shaft or secured thereto by rotatable bearings. The conveyor roller is mounted between frame members of the conveyor for free rotation about the axis of its shaft. The conveyor rollers may be damaged and distorted by the impact from the heavy parts thrown onto the conveyor, and damage may also occur to the bearings which may require that the roller or bearings be replaced. Thus, there has been a need for a conveyor roller mounting device which will absorb and substantially withstand the potentially damaging blows received when heavy parts are thrown onto the conveyor.
A new conveyor roller mounting device has also been needed which replaces the bearing assemblies presently being used to rotatably mount the conveyor roller. It is difficult to assemble conveyor rolls because the bearings must be pressed onto the rotatable shaft and also pressed into the cylindrical roll. This is time consuming, and if a bearing becomes damaged, replacement costs are high. Thus, there has been a need for a simple and inexpensive roller mounting device to overcome the disadvantages present in known mounting structures.
An improved roller mounting device is also necessary to assist in the replacement of present roller drives with the automatic slip coupling assembly of the present invention. The coupling assembly provided herein may be connected to the existing conveyor rolls by using the improved roller mounting device. If the drive roll having the present coupling mechanism is impacted by a heavy load, the roller mounting device will aid in withstanding the impact and there is less likelihood that the power roll will have to be removed for repairs. Thus, the roller mounting device of the present invention provides additional advantages to the slip coupling assembly taught herein as well as advantages for mounting conveyor rolls in general.